Monday, July 27, 2015
Scientists examining ways to combine biofuels and food crops on farms
To do this, resources have to be used efficiently, and crops must be grown in the correct soil and landscape position, Marathe writes. To provide biomass feedstock and reduce runoff of nitrogen fertilizer into runways, farmers can plant bioenergy crops such as willows or switchgrass in rows where commodity crops are not growing well.
Cristina Negri, principal agronomist and environmental engineer at Argonne, told Marathe, "The issue we're working to address is how to design bioenergy systems that are sustainable. It's not idealistic. We wanted to show that it's doable; if we design for specific outcomes, we'll see real results."
The pilot farm site balances economic feasibility, bioenergy and environmental health, Marathe writes. The researchers analyzed parts of the cornfield and discovered the areas with the lowest yield had the lowest nitrogen retention. Planting bioenergy crops could solve the problem because willows and switchgrass, which are perennial bioenergy crops, have more extensive root systems because their lifespans are multiple years. The deeper roots help absorb nitrogen.
If the nitrogen isn't retained by the soil or absorbed by the plants, it is sent into the atmosphere as nitrous oxide, a greenhouse gas, Marathe writes. The project shows that farmers can strategically plant bioenergy crops to increase productivity without wasting money. Argonne researcher Herbert Ssegane told Marathe, "Before this work, the popular idea was 'dedicated field,' where you might convert a large area from corn to switchgrass. But dedicated fields of bioenergy crops are currently inviable in an agricultural setting where the economy is tied to grain. What does pass the cost-benefit test is converting underproductive subareas to an alternative crop." (Read more)